NET Note Says: The passive verb that had been concealed probably indicates that some force was preventing them from responding. It is debated whether God (Robertson) or Satan is meant here. By Lk 24:25 it is clear that their lack of response is their own responsibility.
First, it is observable from the related texts that disciples were in fear and distressed, even paranoid about the perspective of their Master would suffer and die. Jesus began teaching them about His Passion and Resurrection (Mt. 16:21; Mk. 8:31-33) only after the disciples confessed that Jesus is the Messiah, as Peter voiced for the twelve (Matt. 16:16). And the first response of Peter and the rest disciples was a vehement objection as recorded in Matthew 16:22:
They even expressed a fear of going near to Jerusalem. When Jesus wanted to go to Bethany (1.72 miles from Jerusalem) to raise dead Lazarus, Thomas said, “let us also go that we may die with Him (Jn. 11:16). (Here, “Him” refers to Jesus, for Jesus is going there to raise Lazarus). They closed their ears to hear, and minds to accepting the dreadful reality.
In V 44: “... Let these words sink (Θέσθε) into your ears! - Θέσθε, an emphatic imperative denoting to set aside the objection they have.
Fear, unbelief, disbelief, and doubt are all related and can blind our mindminds. If not reversed, it will make an inroad for the adversary into our mind to play.
Devil cannot force children of God into sinning without their consent -i.e. Fall of adam and Eve.
The Scripture says, children of God must resist the devil (James 4:7), and put on the full armor of God (notice, all relate to the Word of God), especially, the sword of Holy spirit, the ῥῆμα of God.
Romans 1:17 says, "For in it the righteousness of God is revealed from faith to faith; as it is written, “The just shall live by faith.” And, "So faith comes from hearing, and hearing through the word (ῥῆμα) of Christ (10:17)
A live fish swim upstream, so does a live Christian. God will not and does not swim for His children.